Speed responsive switch



Jan. l0, 1950 J. l.. PETz ETAL SPEED RESPONSIVE swI'rcH 2 Sheets-Sheet 1Filed June '7, 1947 ATTor-:NEY v,

Jan. `l0, 1950 J. PETZ Erm.

SPEED RESPONSIVE SWITCH 2 Sheets-Sheet 2 Filed June 7. 1947 INVENTORSJOHN CHARLES G. BALLIETT ATTORNEY Patented Jan. 10, 1950 2,493,897 SPEEDRESPONSIVE SWITCH John L. Petz, Poughkeepsie, and Charles G. Balliett,Rochester, N. Y., assignors to International Business MachinesCorporation, New York, N. Y., a corporation of New York Application June7, 1947, Serial No. 753,192

4 Claims. (Cl. 200-80) switches and more particularly to that type of.speed responsive switch which is commonly used in governor controlledelectric motors of the adjustable speed type used in oflice appliances,such as typewriters.

An object of the present invention is to provide an improved speedresponsive switch having better regulation characteristics.

An object is to provide an improved speed responsive member foractuating switch contacts.

An object is to provide an improved switch structure for a speedresponsive switch.

An object is to provide a switch structure which is simple inconstruction, easy to assemble, and more rugged than prior structures ofthis nature.

An object is to provide a simplermeans of adjusting the contacts of aspeed responsive switch to vary the speed.

An object is to provide a speed responsive switch which is moreaccessible for servicing than formerly was possible.

Other objects of the invention will be pointed out in the followingdescription and claims and illustrated in the accompanying drawings,which disclose, by way of example, the principle of the invention andthe best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a side elevation, partly in section, showing the speedresponsive switch attached to an electric motor.

Fig. 2 is a horizontal section on the line 2-2 in Fig. 1.

Fig. 3 is a vertical section on the line 3-3 in Fig. 2.

Fig. 4 is a vertical section on the line 4- 1 in Fig. 2.

Fig. 5 is a side elevation of the speed responsive member as viewed fromthe right in Fig. 2.

In the drawings the reference numeral IU designates an electric motor ofthe universal type, having a .commutator andbrushes. The mainmotor'casing or housing has an extension I0a which acts as a housing forthe speed responsive switch and this housing is closed by an end plateIl which is of the same general shape as the housing I0a in Fig. 3 andis attached thereto by three screws I2 threaded into suitable internalbosses IIlb formed in the housing IIla.

The numeral I3 (Figs. 1, 2, and 4) designates the motor shaft whichextends a short distance into the housing I0a and has secured to it alarge hub I4 on which is mounted the speed responsive This hub isremovably attached to the motor shaft I3 by means of two headless setscrews I5 disposed 90 apart about theperiphery of the hub I4. The hub,at its right hand face (Fig. 2), is transversely slotted at Mb (Figs. 2and 5) to receive a bowed springmember I8 which forms part of acentrifugal weight assembly.

The member I6 is held in the slot IIb by a narrow plate I1 (Figs. 2, 4,and 5) which is mounted on shallow shoulders alongthe edges of the slotNb by staking the metal of the hub I4 in four places (Fig. 5) along theline llc adjacent the slot Hb, the metal being forced over the edges ofthe plate I1 by a chisel-shaped tool in a well known way. Due to thefact that the member I6 is bowed, the placing of the plate I1 in placeslightly compresses the member I6 which is spring-tempered so as to holdsaid member fairmember which controls the governor contacts.

ly firmly in place in the slot ,I lb.

The bowed member I6 has a companion bowed vmember I8 (Fig. 2).. having alarge hole Isa through which the motor shaft I3 passes (Fig. 2) and thetwo members I8 and I8 are held together by casting 2 bean-shaped weightsI9 on the ends thereof as most clearly shown in Figs. 2 and 5, themembers I6 and Il being preferably made of spring-tempered steel and theweight elements I9 of a soft, easily cast metal like lead or tin.

Considering the member I6 as fastened near its center, it is quiteevident that, with rotation of the shaft I3 at a sulciently high speed,the weight members I9 will tend to move radially of the shaft I3 andthereby tend to straighten out the bowed members I6 and I8. Since themember I6 is constrained in the slotl Ilb against movementlongitudinally fof the shaft I3 it is evident that the midpart ofmemberv I8 will tend to move to the right in Fig. 2. By properlyproportioning the weight members I9 and properly tempering the springmembers Il and I 8, the degree of movement of the spring member I8 maybe made suitable for the desired range of speed over which the motor I0is to operate in a specific piece of o'ice equipment, such as atypewriter, in which the motor is used.

The spring member I8 is enlarged where it encircles shaft I3 to form aneye designated I8b (Figs. 4 and 5)- to which is riveted a bridgingmember 20, the side pieces of the bridging member extending throughaxial slots I 4d-in the hub Il and the centr'al part of the bridgingmember .20 extending crosswise of the shaft I3 just in front of theplate I1, as most clearly shown in Fig. 5. It is apparent that the righthand motion of the member I8 in response to increasing speed 3 willcause the bridging member 20 to move to the right in Figs. 2 and 4. Thisbridging member is utilized to actuate the contacts which control thespeed of the motor by shunting resistance in a well known way.

In order to provide ventilation for the motor, there is secured to hub|4 a fan element 2| having the lugs 2|a which act as fan blades to causeturbulence within the motor casing l0. In order to cause the air tofollow more or less of a denite path, there is provided inside thehousing |a a cylindrical member 22 of insulating material which iscentered with respect to the shaft |3 and the armature of the motor I0by means of the bosses |0b, the cylindrical member 22 being merelypressed into the housing. Also pressed into the housing and rmly againstthe right hand edge of the cylindrical member 22 is a disc 23 ofinsulating material having a large hole to permit entry of air into thespace enclosed by the cylindrical member 22.' Thus the member 22 and thedisc 23 act like a fan housing.

The switch mechanism which cooperates with the speed responsive elementshown in Fig. is mounted on the end plate Il so that the entire switchmay be removed for servicing ran adjustment without disturbing any ofits parts. The switch mechanism includes a thick disc 24 oi insulatingmaterial which is freely slidably mounted on two pins Ila riveted to theend plate Il which permit the disc 24 to move axially with respect tothe motor shaft |3 but prevent rotation of the disc. The end plate isprovided with a large hole receiving a cup washer 25 which acts as aseat for a spring 26, the other end of which is seated in a circularrecess formed in the disk 24. This spring normally tends to urge saiddisc to the left toward the end of the motor shaft I3.

Mounted on the disk 24 is a contact support plate 21 (Figs. 2, 3, and 4)which is attached by means of a screw 29 to the disk 24. This contactplate is provided with a terminal screw 29 by means of which a terminallug 30 is screwed to the lower end (Fig. 3) of the plate 21. Theterminal lug 30 is crimped to the stripped end of one of the wires 3|which leads to the resistance controlling the speed of the motor (notshown). To the upper end of the contact supporting plate 21 is secured aspring contact member 32 by means of a screw 33 threaded into the plate21. The contact member 32 has fixed to it a circular post 34 having asocket in which is secured a button 35 which is in axial alignment withthe end of the motor shaft I3 adjacent the cross-piece of the member 20,whereby movements of the member 20 in response to varying speed will becommuni cated to the contact member 32.

The lower end of the contact member 32 (Figs. 2, 3, and 4) carries oneof apair of contact points 36, the other of which is mounted on secondcontact plate 31 attached to the disk 24 by the screw 38. The plate 31is similarly provided with a terminal lug 39 and terminal screw 40corresponding to the terminal screw 29 and lug 30, which lug 39 iscrimped to the other wire 3| leading to the speed controllingresistance. In order to provide maximum security for the wires 3| toprevent them from being detached from' the lugs 39, 39 by vibration,both of the plates 21, 31 are formed with bent-over lugs 21a and 31a,respec tively, which are located over the wires 3| at the time ofassembly and serve to clamp said wires adjacent the lugs 30. 39 to theface of the disc 24 asshowninFigA.

Considering for the moment that the disc 24 is ilxed in the position ofFig. 2, it is quite apparent that, as the motor increases in speed. themember 2|) will move to the right and ultimately will engage the end ofthe button 35 and push the contact member 32 far enough to the right inFig. 2 to open the contacts 36 and remove the shunt on the speedcontrolling resistance. The insertion of this resistance in the motorcircuit will operate in the usual way to reduce the speed of the motorwhich, of course, will cause the member 20 to retreat to the left andpermit the contacts 36 to reclose. By predetermining the position of thebutton 35 in relation to the member 20, it is possible to adjust thepoint at which the contacts open, thereby to adjust the speed of themotor which, once adjusted, will be maintained constant.

For the purpose of adjusting the speed of the motor, means is providedfor adjustably moving the disc 24 toward and away from the member 20.Secured to the inside face of the end plate l I is a ilanged bearingring 40 (Figs. 1 to 4) which loosely, rotatably supports a control lever4| having the pointer and finger piece 4 ia by means of which the levermay be rotated on the inside of the ilanged ring 40 as a bearing, thelever 4| being attached to a large ring-shaped portion 4|b which isrotatable inside the flanged ring 40.

Also rotatable in the flanged ring 40 is a ring 42 which has threeinwardly projecting lugs 42a (Fig. 3) which project inwardly toward thcenter of the ring 42 and engage the lands of a multiple thread 24aformed on the outer cylindrical surface of the disc 24. The lever 4| hasa lug 4|c struck therefrom which extends to the right (Fig. 2) anddownwardly across the right hand face of the ring 42. The lever 4| alsois formed with an extension 4|d (Fig. 3) having a shallow bentover lugof a height approximately equal to the thickness of the ring 42. Thisextension 4|d is provided with a clamping screw 43 and a washer 44, thewasher being on both the shallow lug on extension 4| d and the righthand face (Fig. 2) that is, the rear face (Fig. 3), of the ring 42. Bymeans of the screw 43 and the washer 44 the ringshaped hub 4| b of lever4| and the ring 42 are clamped together so as to rotate as a unit whenthe lever 4| is adjusted angularly to adjust the speed.

It is quite apparent that if the lever 4| is moved to right or left inFig. 3 the ring 42 will be rotated and the lugs 42a will move in a fixedarc of a circle, and by cooperation with the threads 24a will act like anut and cause the disc 24 to move to right or left (Figs. 2 and 4) tobring the button 35 closer to or further away from the member 20,thereby determining the point at which the speed responsive member inFig. 5 takes eiiect to open the contacts 36.

The clamping screw 43 and washer 44 provide a means whereby the motormay be initially set at a definite speed for a definite position of thelever 4| in relation to the scale over which the pointer 4Ia moves whenthe motor is mounted in the machine. For the purpose of facilitatingthis adjustment after the motor has been assembled and particularlyafter the motor has been placed in the machine, the end plate Il isprovided with a large slot IIb (Fig. 3) which permits access to be hadto the screw 43 from the exterior of the motor.

'I'he connecting wires 3| preferably may be in a cable C which entersthe housing |0 through a protecting bushing 45 (Figs. 2 and 3) pressedon the outer wrap of the cable so as to t rather snugly. The bushing 45ts in a hole formed in the casing ilia and the casing ia is slottedbetween the hole for the bushing 45 and the outer or right hand edge ofthe housing. By removing the screws I2 the end plate il may be raisedslightly in Fig. 2 far .enough to disengage the bushing 45 from itshole, the Wires 3| may be slipped out ofthe slot formed in the casingand the entire assembly carried by the plate Il with the attached cableremoved for servicing, repair, or inspection without disturbing any ofthe critical adjustments. Any of the parts most likely to get out oforder which are mounted on the plate il may be readily replaced and theassembly reintroduced in the housing Ilia with a minimum of time.

Furthermore. after the parts have been assembled it is a relativelysimple matter to reset the ring 42 to determine the precise speed of themotor for any given setting of the lever H.

While there have been shown and described and pointed out thefundamental novel features of the invention, as applied to a preferredembodiment, it will be understood that various omissions andsubstitutions and changes in the form and details of the deviceillustrated and in its operation may be made by those skilled in the artwithout departing from the spirit of the invention. It is the intention,therefore, to be limited only as indicated by the scope of the followingclaims:

What is claimed is:

1. In a governor controlled switch, a centrifugal force responsiveelement, a fixed contact member, a cooperating movable contact memberactuated by said element, means for supporting said contact membersincluding a disk having a thread on its periphery, a anged guide, a ringrotatable in said guide and having lugs extending into the lands of saidthread, a control lever connected to said ring, a support for saidguide, and means on said support for mounting said disk for axialmovement on said plate in response to rotation o1' said ring.

2. In a governor controlled' switch, a shaft, a hub mounted on saidshaft; a pair of bow springs arranged with their ends joined and theirconcave sides facing each other and with one spring secured intermediateits ends to said hub, a pair oi weight members secured to the' springs,one at each point of-junction, said weight members tending to straightenwhen the shaft rotates with increasing speed and thereby induce axialmovement of the midportion of the spring which is free at itsmidportion; a xed contact member, a cooperating movable contact memberactuated by the spring which is free at its midportion, means forsupporting said contact members including a disk having a thread on itsperiphery, a flanged guide, a ring rotatable in said guide and havinglugs extending into the lands oi said thread, a control lever connectedto said ring, a support for said guide, and means on said support formounting said disk for axial movement on said plate in response torotation of said ring.

3. A governor controlled switch comprising, a

' support plate, a circular guide flange mounted on said plate, anon-current conducting element disposed in the opening in said flange,.and formed with a threaded portion concentric with said v flange, aring rotatable in said flange and having 4. A governor controlled.'switch comprising, a

support plate, a circular guide flange mounted on said plate, anon-current. conducting element disposed in the opening insa'id flangeand formed with a threaded portion-'concentric with said flange, a ringrotatable in said ange and having threaded engagement with said threadedportion, a control lever rotatable in said ilange and disposedalongsidemsaid-ringf means to adjustably connect said ring and saidlever, means for slidably mounting said disk for axial movement when thesaid ring is turned by said lever, a spring pressing said disk axiallyso as to hold said ring and said lever against said flange, and contactmeans mounted on said disk for bodily movement therewith, a rotatingshaft, a pair of bow springs mounted on said shaft and extendingsymmetrically on opposite sides of the shaft with their ends in contactand their concave sides confronting, one of said springs being securedat its middle to the shaft and the other being free to move axially ofthe shaft to actuate said contact means.

JOHN L. PETZ. CHARLES G. BALHE'II.

REFERENCES CITED The following references are of record in the ille ofthis patent:

UNITED STATES PATEN'IS Number Name Date 1,795,240 Ulmer Mar. 3, 19312,311,409 Merrill Feb. 16. 1948 2,365,657 Naul Dec. 19, 1944 2,438,810Lambert Mar. 30, 1948

